The present invention relates to a fiber-reinforced driveshaft particularly, but not exclusively, for transmitting power in a motor vehicle from the motor to the differential gear unit.
More particularly, the invention relates to an improved fiber-reinforced driveshaft of synthetic plastic material.
A driveshaft of this general type is already known from German published application DT-OS No. 2,851,293. It has a tubular part of glass-fiber reinforced synthetic plastic material in the axially spaced ends of which respective metallic rings are secured. Each ring has an outer circumferential surface which projects partially beyond the end of the tubular part and to which the yoke of a cardan joint--or else an intermediate motion-transmitting member--is welded.
The fiber-reinforced plastic material is wound about the rings in uncured condition and is then hardened. This produced primarily a friction connection between the rings and the tubular part, although the rings may also be provided with projections for better connection with the tubular part.
Prior-art driveshafts of this type are serviceable. However, over a period of time the unavoidable alternating load conditions and vibrations acting on such driveshafts cause the connection between the rings and the tubular part to become loosened, and the service life of such shafts is therefore relatively short. Also, the abrupt diameter reduction of the tubular part in the region of the inner ends of the rings is not conducive to a constant level of force transmission from one end of the shaft to the other; it reduces the force that can be transmitted and may, in extreme cases, even lead to cracking of the shaft at these locations.